FIGS. 1 and 2 show a quick-release holding down device used in a bicycle for holding a part of the bicycle in place. The quick-release holding down device comprises a lever, a bolt, a screw rod, a notched block, a packing plate, a spring, and a nut. The lever has a front opening. The bolt has a screw hole and is secured to the lever and disposed inside the front opening. The screw rod has one end inserted through the front opening of the lever and threaded into the screw hole on the bolt, and an opposite end inserted through the notched block, the packing plate, the spring, and the device to be held down, and then threaded into The screw hole on the nut. The screw bolt can be driven into or out of the screw hole on the nut by the lever. When installed, the lever is turned about the bolt and stopped against a notch on the notched block. This structure of a quick-release holding down device is still not satisfactory in function, because the lever may be turned by error to loosen the screw rod from the nut, causing the device being held down to disconnect from position.
The present invention has been accomplished to provide a quick-release holding down device which eliminates the aforesaid problem. According to the preferred embodiment of the present invention, the quick-release holding down device comprises a headed screw rod, which is inserted through the device to be held down and then screwed up with a nut, a lever is turned about a pivot on the head of the headed screw rod, and a headed lock bar controlled by a combination lock provided in the lever for preventing the lever from turning about the pivot when the numbers in the lock are incorrect.